1. Field
The invention is in the field of protective helmets for welders wherein lenses are provided, one being an eye-protective lens mounted for movement into and away from the welder's line of sight and another as a cover for the first one.
2. State of the Art
Most welding helmets in use today have a fixed, light-filtering lens mounted therein, the helmet itself being pivotally mounted on a headband so that the entire helmet can be pivoted upwardly over the head of a welder when he is not actually welding, thereby enabling the welder to see without the light-filtering lens. While this is common current practice, the face and eyes of the welder are left unprotected when the helmet is raised, except for protective eyewear that may be (but is usually not) worn by the welder beneath his or her helmet.
Various constructions for a welder's helmet with a light-filtering lens, which, itself, can be conveniently moved out of and back into the line of vision to thereby leave the helmet in place in front of the welder's face, have been proposed in the past. Some have also included a clear but protective cover lens to protect the welder's face and eyes when the light-filtering lens is moved out of the way and to provide a cover for the light-filtering lens. Helmets which merely pivotally mount the light-filtering lens at its top so that a welder can pivot such lens up and out of the way, leave this lens projecting undesirably outwardly from the face of the helmet.
Reference is made to Manz U.S. Pat. No. 3,768,099, issued Oct. 30, 1973, which provides a light-filtering lens within a carrier frame that is slidable upwardly and downwardly in an fixed frame at the inside front wall of the face-protective shell of a welder's helmet. Such front wall has a sight opening covered by the light-filtering lens in the down position of the carrier frame. However, the size of such lens is limited by the clearance space that exists from the upper margin of the sight opening to the top wall of the helmet shell. With the stationary frame providing a track for the movable carrier frame, backward movement of such carrier frame is restricted as it moves upwardly until it has moved upwardly sufficiently far to be substantially clear of the track but so that its lower margin will pivot therein for backward movement.
Since the carrier frame incorporating the light-filtering lens of this Manz patent has to nearly clear the stationary frame before backward movement is possible and since overhead clearance is limited due to the proximity of the top of the helmet shell, the size of the eye-protective lens is limited. A carrier frame for a relatively large light-filtering lens will not clear the top and sides of the stationary frame for effective backward movement, nor will it fit into a retracted position upwardly of the sight opening at the front of the helmet shell. This is because such retracted position is solely behind the front face of the helmet shell. Restriction against backward movement of the carrier frame does not allow for its retraction under the top of the helmet shell.
A welder's helmet having a retractable lens of large size has long been desired, but providing for same has remained a problem. Even though U.S. Pat. No. 4,853,973 of Boochard apparently provides a helmet with a large lens, the front or visor portion of the helmet shell is a separable part thereof and is pivotally mounted so as to move up and out of the way, leaving the welder a clear and unobstructed view through a clear protective lens, which remains in place. The pivotal arrangement is complicated, and the pivoted portion of the welder's helmet projects beyond the remainder of the helmet when raised and interferes with movement in tight spots.